The present invention generally relates to implantable medical devices. More particularly, the invention relates to telemetry modulation protocols for transmitting data to and from an implantable medical device.
The medical device industry produces a wide variety of electronic and mechanical devices for treating patient medical conditions. Depending upon the medical condition, medical devices can be surgically implanted or connected externally to the patient receiving treatment. Physicians use medical devices alone or in combination with drug therapies and surgery to treat patient medical conditions. For some medical conditions, medical devices provide the best, and sometimes the only, therapy to restore an individual to a more healthful condition and a fuller life.
Medical devices are commonly used today to treat patients suffering from various ailments. Implantable medical devices can be used to treat any number of conditions such as pain, incontinence, movement disorders such as epilepsy and Parkinson""s disease, and sleep apnea. Additionally, use of medical devices appears promising to treat a variety of physiological, psychological, and emotional conditions.
One type of medical device is an Implantable Neuro Stimulator (INS). The INS is implanted at a predetermined location in the patient""s body. The INS generates and delivers electrical stimulation signals at neurostimulation sites or areas to influence desired neural tissue, tissue areas, nervous system and organs to treat the ailment of concern. The stimulation sites can also include the spinal cord, brain, body muscles, peripheral nerves or any other site selected by a physician. For example, in the case of pain, electrical impulses may be directed to cover the specific sites where the patient is feeling pain. Neurostimulation can give patients effective pain relief and can reduce or eliminate the need for repeat surgeries and the need for pain medications.
An INS system generally includes an implantable neuro stimulator (INS) (also known as an implantable pulse generator (IPG)), an external physician or physician programmer, a patient programmer and at least on electrical lead. The INS can be powered by an internal source such as a rechargeable or non-rechargeable battery or by an external source such as a radio frequency transmitter. The INS contains electronics to generate and send precise, electrical pulses to the stimulation area to provide the desired treatment therapy.
The physician programmer and patient programmer are external devices that allow a physician or patient to communicate with the INS. The physician programmer is an external device that allows the physician to create and store stimulation therapy programs for the patient to be delivered by the INS. The patient programmer is an external hand-held device that allows the patient to optimize the stimulation therapy programs delivered by the INS. Typically, physician and patient programmers communicate bi-directionally with the INS, via RF telemetry signals. The bi-directional communication between the medical device and the physician or patient programmer is typically accomplished via a telemetry module. The physician programmer, the patient programmer and the medical device each have respective telemetry modules that allow for bi-directional communication between the medical device and the programmers. The bi-directional telemetry communication, between the medical device and the physician or patient programmers is typically conduced at frequencies in a range from about 150 KHz to 200 KHz using existing telemetry protocols.
Existing medical devices and programmers communicate through various telemetry protocols that are designed for the particular programmers and medical devices being used. For example, a protocol between a physician programmer and a drug pump to deliver medicine to relieve pain is usually different than a protocol for a patient programmer and an INS to deliver electrical stimulation therapy. A non-exhaustive listing of existing communication protocols include Telemetry A, Telemetry B, Brady Telemetry, etc. At present, there is no standard or uniform communications protocol for medical devices and programmers. In addition, existing protocols tend to be complex and difficult to implement in the field. As a result, existing protocols suffer reliability problems. Also, existing protocols cannot typically be interchanged for use by different products since the various existing protocols are typically product specific.
The lack of protocol standardization leads to higher costs for consumers needing such medical devices since products and protocols must be tailored to their specific needs and application. Additionally, the manufacture of products and components using the various protocols is costlier since the products cannot be efficiently produced for use with a standard protocol.
For the foregoing reasons, there is a need for a standardized telemetry communications protocol or system protocol that is simple in design, reliability and implementation. There is a need for a standardized telemetry protocol that can be used in a wide array of medical devices and programmers for patient treatment.
It is an object of the present invention to provide an apparatus and method to provide a telemetry protocol system to support and control the use of telemetry in a wide array of medical devices and products used in providing patient treatment.
It is an object of the present invention to provide an apparatus and method to provide a telemetry protocol system for use in medical devices to provide electrical stimulation therapy.
It is yet another object of the present invention to provide a standardized telemetry system that is a sophisticated and reliable design that is easy to implement at the device level and will support a wide range of medical devices.
The present invention provides an apparatus and method for a standardized telemetry system that automatically selects a modulation protocol configuration to establish a reliable symmetric telemetry link between medical devices and programmers. The modulation protocol configuration selected permits the establishment of an appropriate telemetry link and data transmission rate.
In a preferred embodiment of the present invention, the standardized telemetry protocol will automatically select a symmetric modulation protocol configuration based upon the type of hardware used to communicate between the implanted medical device and the programmer. The symmetric modulation protocol configurations are comprised of a modulation format and a corresponding data rate capability or transmission speed. Any one of the following modulation formats may be automatically selected: (1) a pulse or burst width modulation (PWM) format; a pulse or burst width modulation (PWM) plus pulse interval modulation format; (3) a modified phase shift keying (MPSK) modulation format; (4) pulse position modulation (PPM); or (5) pulse interval modulation (PIM). The corresponding data rate capability will depend on the type of communications hardware used in the devices communicating, Accordingly, a modulation protocol configuration is automatically selected that is best suited for the hardware being used to communicate between the implanted medical device and the programmer. Moreover, the modulation format used to communicate during a communications session can be continuously and contemporaneously switched from one modulation format to another.
In accordance with the present invention, there is also provided a method for establishing a communications link for transmission of information between a medical device and a programmer. The method comprises the steps of receiving a message envelope at a telemetry module, interpreting the message envelope to automatically select a symmetrical modulation protocol configuration based upon the message envelope, and establishing the communications link between to two telemetry modules using the selected modulation protocol configuration.
An apparatus and method for a telemetry system that automatically selects a symmetric modulation protocol configuration can be used with any number of programmer and medical devices requiring the use of telemetry communication, including an INS, an ENS, a pacemakers, a defibrillators, a cochlear implants, implantable diagnostic devices for detecting bodily conditions of certain organs, like the brain or the heart, and drug delivery systems having an implantable pump.